Justices’ Texas Redistricting Ruling Likely to Help G.O.P.

The unanimous decision said that redistricting is primarily a job for elected state officials and that the lower court had not paid enough deference to maps drawn by the State Legislature, which is controlled by Republicans. The justices sent the case back to the lower court, extending the uncertainty surrounding this major voting-rights case.

“In the absence of any legal flaw in this respect in the state’s plan, the district court had no basis to modify that plan,” the justices said, talking about state House districts in north and east Texas.

The new maps to be drawn by the lower court could play a role in determining control of the House of Representatives. Democrats need a net gain of 25 seats to take back the House from Republican control, and both parties are fighting for every advantage in the battle for the House majority. Experts in election administration said the new maps could influence outcomes in perhaps three Texas districts.

“A district court should take guidance from the state’s recently enacted plan in drafting an interim plan,” the Supreme Court’s unsigned decision said. “That plan reflects the state’s policy judgments on where to place new districts and how to shift existing ones in response to massive population growth.”

The changes to the electoral maps were required because Texas grew by more than four million people in the last decade, with about 65 percent of that growth coming in the Hispanic population. The growth entitled the state to four additional House seats. In rejecting significant aspects of the Legislature’s maps, the lower court said it had tried to ensure that Hispanic voters had adequate opportunities to elect candidates of their choice, adding that political considerations had played no role.

Justice Clarence Thomas concurred only in the result and said he would have instructed the elections to proceed under the Legislature’s maps.

In a second development on Friday, the justices blocked a decision of a federal court in West Virginia in another election case while the justices consider an appeal. The West Virginia case concerns whether that state’s three House districts must be absolutely equal in population.

In the Texas case, the justices acted just 11 days after hearing arguments. Primaries in Texas had already been moved back to April. For those primaries to proceed, officials there said, an answer from the courts was needed by Feb. 1.